The present invention relates to depilatory devices for removing body hair and, more particularly, to devices for removing unwanted body hair by uprooting the hair.
A large number of depilatory devices have been proposed through the years. Depilation can be effected in one of two basic processes. In one process, implemented by shavers of various types, strands of hair are cut, typically in the vicinity of the skin, leaving the roots intact and in place beneath the skin surface. In the other basic process, which will henceforth be referred to as `hair removal`, hair is removed without cutting the strands, typically by vigorously pulling the hair strands so as to uproot the hair and remove the entire hair, including the roots.
In a number of applications, such as in the depilation of women's legs, it is considered preferable to uproot hair rather than to cut it since the removal of the roots considerably slows, and to some extent permanently thwarts, the growth of replacement hair, and leaves the skin relatively smooth and virtually free of hair for relatively long periods of time. By contrast, cutting the hair, as by shaving, does nothing to interrupt or disrupt the hair growth and often leads to the early appearance of unsightly stubble as the cut hairs continue to grow.
Processes for the mechanical uprooting of hair generally involve grasping one or more strands of hair and vigorously pulling on the hair so as to remove the entire hair, including its roots. Care must be taken that the hair thus grasped and pulled is not inadvertently cut in the process. Care must also be taken to ensure that the pulling of hair occurs sufficiently quickly that the user does not sense an unacceptable amount of pain or discomfort. As may well be appreciated, everything else being equal, the quicker the pulling action, the less painful is the uprooting.
Various devices for accomplishing hair removal have been described and reviewed in my earlier U.S. Pat. Nos. 4,935,024 and 5,057,115 which are incorporated herein by reference for all purposes as if fully set forth herein.
Several of the proposed hair removal systems involve the use of tilted discs which come together at a point to grasp one or more strands of hair. In such systems, strands of hair are grasped at the point where the two discs momentarily come together and are pulled as the discs continue to rotate. Further rotation of the discs causes the distance between the discs to increase, allowing the uprooted hair to drop from the device.
Such systems generally suffer from at least two disadvantages. First, the pinching of a strand of hair at the point of contact between the two discs often results in the undesired cutting of the hair, rather than in its desired uprooting. Second, since the discs are only in contact momentarily and at a single point, a hair which is grasped at the point of contact will be released soon thereafter as the discs continue to rotate. Often, such release will occur before the hair has been displaced sufficiently to be uprooted. The result is that the hair will remain in place, firmly attached to the skin by its root. Such a phenomenon is unfortunate since, not only does the hair remain in place unremoved but the user has also had to suffer needless discomfort or even pain as the hair was pulled partially prior to being released.
Other of the proposed hair removal systems involve the use of cams to alternately bring discs, or similar members, together and apart periodically to effect the grasping and releasing of strands of hair. In some cases, the discs or other members are flattened at their outer periphery so as to provide a region where hairs can be grasped which is larger than the single point afforded by a pair of ordinary discs. All such cam-based systems suffer from the disadvantage that the use of cams induces an undesirable vibration in the device, which is transmitted to the user and reduces his or her level of comfort.
In addition, some cammed systems involve the slight displacement of the traps from their undisplaced position, such the trap is effected in a location which is slightly displaced from where the trap elements were prior to the formation of the plate. A difficulty with this arrangement is that shorter hairs which are initially introduced into the trap area may escape the trap before the trap is closed because of the slight displacement of the trap elements.
Efforts have been made to increase the size of the regions over which hair can be grasped by using discs or similar elements which are in some sense resilient. One such system is disclosed, for example, in U.S. Pat. No. 4,807,624. However, such systems are also not free from difficulties. Specifically, since such a system has a certain amount of resiliency, or `give`, once hair has been grasped, the grasping member has a tendency to be pulled by the hair toward the skin. This prolongs the act of uprooting the hair and accordingly increases the amount of discomfort or pain experienced by the user.
Recently, Philips N.V. has been marketing a hair remover under the name of New Satinelle which attempts to overcome many of the above-described limitations. The Philips device features a number of discs which are stacked on a rotatable assembly made up of three straight parallel shafts. The two end walls which touch the outer discs, which are different in construction from the intermediate discs, are angled so as to tilt one portion of each of the outer discs approximately perpendicular to the shafts. Each of the discs of the Philips device is made up of a metal portion and a complex integral plastic portion which includes a number of complicated protrusions and recessions designed to transfer the tilt of the outer discs to the intermediate discs. The tilt produces regions where adjoining discs alternately come together to form a temporary trap for the hair and move apart to release the uprooted hair.
While the Philips device appears to overcome several of the disadvantages of the previously known systems, the device displays at least three difficulties. First, the Philips design calls for the use of two different disc assemblies, which unnecessarily complicates the assembly and maintenance of the unit. Second, close inspection of the Philips disc assembly reveals that the assembly provides only one hair trap per rotation of each disc, which makes it necessary to use a relatively large number of rather closely-spaced discs. Finally, it is to be noted that the Philips device is asymmetrical and operates properly only when the discs are rotated in one sense and not the other.
There is thus a widely recognized need for, and it would be highly advantageous to have, an inexpensive and rugged hair removal device which is capable of efficiently grasping hair over a large trap area, without undesired displacement, and which can then hold the trapped hair long enough to quickly, and relatively painlessly, uproot the hair, which device will provide a relatively large number of traps per rotation of each disc, will be symmetrical and therefore function equally well in either rotational sense, and will make use a plurality of disc assemblies which are all identical, for easy assembly and maintenance.